2 - methyl - 7 - hydroxy - tetrahydrophenanthrene - carboxylic acid derivatives and the production thereof



Patented Feb. 28, 1950 2 METHYL 7 HYDROXY TETRAHYDRO- PHENANTHRENE CARBOXYLIC ACID DE- RIVATIVES THEREOF AND THE PRODUCTION George M. Picha, Chicago, 111., and Robert P. Jacobsen, Shrewsbury, and Gregory Pincus, Worcester, Mass., assignors. toG. D. Searle & 00., Skokie, Ill., a corporation of Illinois No Drawing. Application December '17, 1947, Serial No.792,324 a 19 Claims.

This invention relates to dihydroxytetrahydrophenanthrenealkanecarboxylic acid derivatives, and to the preparation thereof. In particular it relates to tetrahydrophenanthrene compounds having the general structural formula wherein A, attached to carbon atoms 1 and 2, represents a lactone grouping having the empirical formula Cal-I402 or alcoholic and aliphatic carboxylic acid groups having an aggregate empirical formula C3H6O3, which by'lactonization can form a lactone grouping, and wherein X represents a monovalent oxygen function such as hydroxyl and related groups, including acyloxy, alkoxy and aralkoxy groups. This invention relates also to salts and esters of the foregoing carboxylic acids.

The compounds to which thislnvention relates are obtained by oxidizing equilenin, or an ester or ether thereof, with an organic peracid, or hydrogen peroxide, in an inert solvent. Equilenin has the structural formula l By oxidation of equilenin or its esters with a peroxide or a peracid there is cleavage Ofjthe cyclopentanone ring with the resultant formation of-a lactone grouping. The lactone :ring may be opened, forming an alcoholic hydroxyl These groups can be relactonized by treatment with acid or by warming.

From the foregoing it follows that the Z-methyl 7 hydroxy 1,2,3,4. tetrahydrophenan- .45 radical and an alkanecarboxylic acid group.

threne nucleus which is 'formed in, the compounds of this invention-is thesame asthat present in equilenin, the parent substance.

The oxidation is preferably conducted in the presence of an acidic,catalyst', although such- V 2 4 catalyst is not required. Suitable as catalysts are strong organic and inorganic acids which are not susceptible to oxidation or reduction. Among these are sulfuric, phosphoric, benzenesulfonic, toluenesulfonic, alkanesulfonic and alkylated sulfuric acids, including methyl sulfuric acid, ethyl sulfuric acid, and the like. A neutral or acidic medium has been found to be satisfactory for the process. The preferred medium is a lower alkanoic acid such as acetic or propionic acid. Suitable also are stable neutral solvents such as lower tertiary alcohols, ethers, hydrocarbons and-halogenated hydrocarbons, as for example, t-butyl alcohol, chloroform and carbon tetrachloride. Mixtures of water and watermiscible inert organic solvents are also satisfactory. The processes can be carried out over a fairly wide range of temperature, varying from about 5 C. to as high as C. The oxidizing agent is preferably peracetic acid in glacial acetic acid. However hydrogen peroxide in aqueous acetic acid is nearly as eflicient. Suitable also are other organic peracids such as lower aliphatic peracids, perbenzoic acid, and the like. The oxidizing agents which are suitable for our processes are peroxides and have in common the The 3-hydroxyl radical of equilenin is preferably protected during the oxidation, although thisis not essential. For this purpose we prefer to use the acetyl group, as equilenin acetate is one of the more readily available derivatives.

.Other acyl, alkyl and aralkyl radicals are equally suitable, among them being the propionyl, benzoyl, methyl, ethyl, propyl, benzyl, naphthylmethyl and related groups. The acyl and arylmethyl radicals are readily cleaved after oxidation by hydrolysisor hydrogenolysis, affording the free hydroxyl' radical if desired.

Salts of the carboxylic acids to which this invention relates; are most conveniently produced by treatment of the corresponding lactone with an alkali, generally with warming. The lactone ring is thereby opened and the salt is simultaneously formed. Concentration of the solution causes precipitation of the desired salt. Similarly the salt may be prepared in alcoholic alkali and precipitated by the addition of a solvent in which the salt is insoluble, as for instance, ether or benzene.

The carboxyl group of the acids obtained by the opening of the lactone ring may be converted to esters by suitable methods. Warming causes relactonization," which is a special type of esterification, viz., inner-ester formation; Treatment with diazomethane and other diazo hydrocarbons such as phenyldiazomethane results in the formation of'themethyl and-benzyl and related esters. 1

The pituitary gland, as the so-called master gland of the body, elaborates and secretes certain hormones which control .and stimulate the declines markedly. As a result, secretions of gonadotrophin .(thehorm'one or hormones which stimulate the activity of the "gonads'to secrete estrogenic hormones) and ptherhormone's-bythe pituitary often reach excessivelevelspsince they are no longer restrained byithe presence'of'estro genic hormones. "This'tendstp cause many er .the unpleasant and undesirable *symptoms freguently associated with the menopause. The administration of gestrogenichormone substances is known to control such 'symptomaatleast' in ,part through their pituitary "inhibition, but it produces undesirable estrogen'ic *e'iirects "at the same time. Thusit will be seenthat a'substance which will effectively Linhibit certain pituitary activity and at'the sametim-e-not produce'estrogenie activity is a' useful, valuable and desirable addition to the field 'o'ftherapeutics. It is "the object of this invention to provide 'such substances.

"Ihe 'polyhydrophenanthrene lactones and dcrivatives thereof which comprise this invention are new anduseful-compositi'ons in the field o'f therapeutics by "virtue .of their ability *to affect the secretion of hormones'by'the-pituitary gland. 'More particularly, the "new compositions 'of this invention are uniquely useful and valuable "in medicine for the control of certain glandular disorders, because they. possess "little or "no estrogenic activity.

The tetrahy'drophenanthrene lactones and derivatives thereofmay be prepared "as specifically tdisclosedin the .following "examples. "These examples are illustrative :in' nature and'are not-intended'to limit our invention'inanyway.v"1'ire relative :amounts of "materials are given in parts :by weight unless otherwise .TIDtBd.

sample 11 .is dissolved in about parts of "glacial acetic acid, andaboutl'? parts of "a-solution of'p'eracetic acid in glacial acetic acid are "added "(this-"5011i tion contains approximately 010012 'mole of peracetic acid in each cubic centimeter) Themii'i- 4 ture is maintained .at about 10 centigrade for from to hours. At the end of this time the 'crude product. is precipitated by .the addition :of @ailarge 'excessof water,zand it purified by one or more recrystallizations from methanol or =other suitable solvents. By this procedure the .acetoxy lactone of composition C2oH2oO4 is obtainedinzaflieldioirabout 50% of the theoretical. The acetoxydactone, when pure and anhydrous, melts at 315650415628 C. This compound is believed to have the structural formula 'It -wilhbe 'obviousito 'one skilled 'inr-the artthat the preparation can 'also be carried out modified-reaction conditions. For example, 'satis factory results have "also been :obtained by carry} ing out the reaction at atemperature of 35 for a period of only about 24 hours. We prefer to carry out the reaction using a lower temperature and a longer reaction time.

oxidizing agents other than peracetic acid can also be employed. For example, the lactone can also be prepared from equilenin acetate by using 30% aqueous hydrogemperoxide in a solution of acetic acid as the oxidant.

Example 2 &A solution of 0-62 :gram .of .equilenin .acetate .in;6 milliliters of acetic .acidand 1.5 :ml. of ..30,% ,aqueoushydrogen .peroxide :is kept .at .35" C. .for :60.-hours. The reactionmixture .is .diluted with -water,-.causing the-,precipitation-of a. yellow, .partlallycrystalline solid.in;30-.40%, yie1d. .Themelt- .ing point after recrystallization .from aqueous .methanoliis 142-147 .C. When 0.72 .g. of .this material is hydrolyzed with aqueous methanolio ,zpotassiumihydroxide andrthecold,,methanol-free .solution is saturated withcarbon .dioxide, .there. is

precipitated 0.23 g. ..of .equilenin. The .filtrate :is strongly r-acidified .and warmed, .causing .the separation of 0.35 g. of sparingly soluble, brown solid. This after acetylation with acetic anhydride and pyridine, and recrystallization from aqueous methanol, forms fine, colorless needles of the acetoxyjactone of M. P. -15? C.

Example 3 The preparation of. the,.hydroxy lactone of composition CIBHIEOB from the acetoxy lactone of composition Gaul-12004 is .carried out by an alkaline saponification of the latter compound, followed by acidification ofthe reaction mixture and 'heating to effect relactonization.

In a typical --preparati-on, '1 part of the -ace'toxy "lactone *is suspended in about '70 parts of :a 2% :solution of sodium hydroxide "in water. This mixture is heated at about 100 C. ror approxi- -.mately'two hours. At th'eend of this time' th'e acetoxy lactone is completely in solution (as-the disodium salt of the dihydroxyzaci'd which results ffrom the saponification cf the acetoxy group andthe opening of the lactone-ring). The .rnixtureis diluted iwithabout "200 parts 'of water, "heated again almost vtoboiling, and'treatedwitii excess'hydrochloricacid; 'About"95%o'f"the theo 'reticalamount' of the hydroxy lactoneisprecipi- 75 "tatedasa'pink,crystallinesolid whichisTemoved Example 4 The preparation of the methoxy lactone of composition CmHzoOs is carried out by treating an alkaline saponification mixture of the acetoxy lactone of Example lwith dimethyl sulfate, or by treating an alkaline solution of the-:hydroxy lactone with dimethyl sulfate, or by refluxing the hydroxy lactone with methyl iodide in the. pres-.-

ence of silver oxide, followed by saponification of the methylation product (to convert any ester which may be formed to the salt of the free acid), acidification, and relactonization.

In a typical preparation, l-part of acetoxy lactone is saponified by heating it at 100 C. for 2 hours with about 70 parts of 1% sodium hydroxide solution. The clear solution which results is shaken-at 50-60" C. with about 3 parts of dimethyl sulfate, added in small. portions, -a1ter--.-

nately with sufiicient sodium hydroxide" solution to keep the mixture alkaline. The; mixture is thenacidified (to Congo Red) with hydrochloric acid, and the solid product is removed by-filtration. It is resaponified with aqueous sodium hydroxide as disclosed inExample 2, and; this mixture is treated while hot with excess hydrochloric acid. The crude methyl ether of the lactone precipitates and is removed by filtration and purified by recrystallization from methanol, giving a yield of about 80% of the theoretical amount. The melting point of this compound is 197.3- ,199.5 C. The methoxy lactone is believed to have thestructuralformula 7 i CHIO Example The dihydroxy acid of composition C1sHzoO4 is prepared by cautiously acidifying an alkaline .saponification mixture of the acetoxylactone or hydroxy lactone. i

In a typical preparation, 1 part of, the acetoxy lactone is suspended in about 70 parts of a 2% solution of sodium hydroxide in water. This mixture is heated at about 100 C. for approximately 2 hours. At the end of this time the acetoxy lactone is completely in solution (as the clisodium salt of the dihydroxy acid which results from the saponiflcation of the acetoxy group and the opening of the lactone ring). The solution is chilled in an ice bath and acidified to pH 5 by the dropwise addition, with constant shak- *10 most of the remainder of the product can be mg;oi'coldj'dilutehydrochloric acid. The addition of exoesshydrochloric acid, or warming the mixturegwill cause relactonization.) The crude Droductis collected on a filter as-a tar; It is precipitated fromac'e'tone solution by'the addition of water, and the solid product obtained in this manner is washed well withwater and purl-'- fled by one ormore recrystallizations from a mixture of ethyl acetate and benzene. The yield is about 55% of the theoretical amount, and

recovered from the aqueous liquors as the lesssoluble hydroxy lactone. The dihydroxy acid is believed to have the formula CHI -on I When the melting point of the dihydroxy acid is determined in the conventional manner, it is converted into the hydroxy lactone before fusion and exhibits the melting point behavior characteristic of the latter compound. The melting point of the dihydroxy acid, when determined instantaneously in a pre-lieated bath, is "C. It evolves water vapor during the process of fusion and immediately resolidiiies as the hydroxy lactone.

Erample 6 The methoxy lactone (Example 4) is saponifled in 2% sodiumhydroxide solution according to the general method of Example 3. The resulting solution of the sodium salt of the methoxy hy- 'droxyacid is carefully neutralized in the cold t on -CH2CH3O O OOH ome we claimr Y i H 1. A new composition of matter having the. structural formula wherein A represerits membenof the greatest f'sistingof a lactone grouping having the e'm'pirical formula C3H402 and the corie'spon'di-n'g 'hydroxy masseuse wherein A represents ea lactone grouping having the empirical formulaCiHrOz and R is a member of the group consisting of hydrogen, lower alkyl, and.:lowersaikanoyl ra'dicals.

3. A new composition or matter having the structural formula wherein A representsihydroxylan'tl'ealiphatic car-- 'boxylicacid groupshaving-an aggregate empirical formula C3H503 'and -R is :a member; of ,the group consisting of hydrogen, lower alkyl, .and :lower alkanoyl radicals, and :alkalirmetal salts thereof. 3 4. A new composition of matter having the structural formula 'wherein'A represents'a lactone grouping having "the empirical (formula 'C'HiOz and R is zafl'ower talkanoyl radical.

5. vA 'new -'com position "of matter having .the

structural formula v wherein A represents a lactone grouping having the empirical formula Cal-I402.

6. A new composition of matter shaving the structural-formula .CGH:

wherein A representsn lactone grouping having the-empiricaliormulaicaHtCh. i

$7. inew composition .pf matter "having the structural formula wherein A represents a lactone grouping having the empirical formula Cal-I402 and X represents a lower alkoxyl radical.

8. A new composition of matter having the structural formula.

wherein A represents a lactone' grouplng 'having the empirical formula C3H4O2.

-9.;A 'new composition :of matter having tlre structural iformula wherein 'A represents alcoholic "and aliphatic 'carboxylic "acid groups 'having'an aggregate em pirical formula 0311603, and lower alkyl esters and salts "thereof.

"10. A new composition of matter having -the structural formula wherein A represents hydroxyl andaliphatic carboxylic acid groups having an aggregate empirical formula CsH'sOa and X represents a lower alkoxyl radical andJower alkyl esters and salts thereof.

11. A new composition of matter having the structural formula wherein .A represents 'hydroxyl and aliphatic "carboxylic acid groups having an aggregate-empirical formula CHaOa and salts thereof.

' '12. A new composition of matter having the 's'tructuralformula 9 whereinA represents hydroxyl and aliphatic carbomethoxy groups having an aggregate empirical formula Cal-180a.

13. The process of producing a compound having the formula with an oxidizing agent of the group consisting 10 of hydrogen peroxide and organic peracids, in an inert solvent. 1

14. The process according to claim 12 wherein the oxidizing agent is peracetic acid.

15. The process according to claim 12 wherein the oxidizing agent is aqueous hydrogen peroxide in acetic acid.

16. A hydroxy lactone as in claim 5 having an empirical formula C1sH1sO3 and a melting point of 292 C. (metal block, one minute).

17. An acetoxy lactone as in claim 6 having the empirical formula 0201-12004 and a melting point of 155157.5 C.

18. A methoxy lactone as in claim 8 having the empirical formula C19H20O3 and a melting point of 197.3-199.5 C.

19. A dihydroxy acid as in claim 9 having the empirical formula Ciel-12004 and a melting point of, C. when determined instantaneously in a pre-heated bath.

GEORGE M. PICHA. ROBERT P. JACOBSEN. GREGORY PINCUS.

REFERENCES CITED The following'references are of record in the file of this patent:

Doisy, Endocrinology, Vol. 30, 1942, page 936. Heer et a1. Helvetica Chimica Acta, v. 28 (1945) pages 1506-1508.

Certificate of Correction Patent No. 2,499,257 February 28, 1950 GEORGE M. PICHA ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 53, for 155157 0. read 155-157.5 0.; column 6, line 1, before The insert an opening parenthesis; line 75, for hydroxy read hydroxyl;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 4th day of July, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant Uommz'ssz'oner of Patents. 

1. A NEW COMPOSITION OF MATTER HAVING THE STRUCTURAL FORMULA 